ISA 428 Troubleshooting Guide

Article Applies to: ISA: 428 and 428 MkII

No LEDs illuminated • Is the POWER switched on? • Is the correct mains voltage being used for your unit? If not, the fuse may blow, requiring the correct fuse to be refitted. (Click here to find the fuse rating for your unit.)

No output when using one of the MIC INPUTs • Is the POWER switched on? • Is the MIC LED next to the SELECT switch illuminated? • Is the LEVEL set correctly? • For microphones that require phantom power, is the +48V switch engaged? (If you are unsure whether your microphone requires phantom power, check the user guide for your microphone.) • Is the Insert In switch engaged? • Is there a fault with your mic/mic cable?

No output when using one of the LINE INPUTs • Is the POWER switched on? • Is the LINE LED next to the SELECT switch illuminated? • Is the LEVEL set correctly? • Is the Insert In switch engaged?

No output when using one of the INSTRUMENT INPUTs • Is the POWER switched on? • Is the INST LED next to the SELECT switch illuminated? • Is the LEVEL set correctly? • Is the Insert In switch engaged?

One of the FILTERS is not working • Is the FILTER IN switch engaged? • Are the dials set to act on frequencies that are present in the signal?

No word clock lock • Is your external word clock source transmitting word clock? • Is the sample frequency set to match that of the word clock-transmitting device? • Is an external word clock cable needed and, if so, is it connected? (See clocking regulations in the GENERIC SETUP) • Has the digital card been initialised? (See A/D Card section in GENERIC SETUP) • Has the front panel switch been set to receive External Word Clock?

No output from the digital output option • Has the A/D card been initialised? If not, simply hold down any front panel switch whilst powering the unit up. • Is the sample frequency set correctly? If the sample rate is set to 176 or 192kHz then no signal will be transmitted from the ADAT O/Ps. • Is the receiving device set to receive the correct resolution (16-, 20- or 24-bit)? • Is the receiving device set to external sync? (See DIGITAL in GENERIC SETUP) • For AES/SPDIF, is the correct type of lead being used? • For AES at 192kHz, is the receiving device a one- or two-wire system?